Circular Breathing A5E
Transmutation cantrip
You begin carefully regulating your breath so that you can continue playing longer or keep breathing longer in adverse conditions.
Until the spell ends, you can breathe underwater, and you can utilize bardic performances that would normally require breathable air. In addition, you have advantage on saving throws against gases and environments with adverse breathing conditions.
At higher levels
The duration of this spell increases when you reach 5th level (10 minutes), 11th level (30 minutes), and 17th level (1 hour).
Source: Adventurer's Guide (EN Publishing) · License: Creative Commons Attribution 4.0 / OPEN GAME LICENSE Version 1.0a details